While many applications exist for laser produced plasma (LPP) equipment, perhaps the most common use is in photolithography for patterning semiconductor wafers. Specifically, the equipment employed for photolithography of semiconductor wafers generates high-energy plasma radiation, which is then captured and focused on the semiconductor wafer during photolithographic operations. Currently, the most common approach to generating the needed energy is to focus high intensity radiation, such as a stationary pulsed laser beam, on a moving target tape (e.g. copper, stainless steel, etc.) in order to generate x-rays. The intersection of the radiation and the tape within the target area defines a point source (at each laser pulse) from which the x-rays radiate.
Typically, in such a process, holes or spots are formed on the target tape. Since the spatial position of the x-ray point source must be stationary, the tape must move in a pattern to allow a fresh portion of the tape to be exposed to each succeeding laser pulse. The conventional approach for a target tape is to move the tape from a feed reel to a collection reel, and which utilizes a single straight line along the tape for the series of laser pulses. Other approaches may steadily move the tape horizontally as it advances through the point source area (or horizontally moving the tape after each pass from one reel to another) so that the substantial width of the tape may be used, however, a benefit to the straight-line approach is the ability to use narrow tape, which may prove to be less in overall expense. In addition, the tape in these systems is often warped by the ablation even after only one pass, which makes multiple passes for the same tape, even if moved horizontally, inefficient and difficult to do.
Disadvantages to conventional equipment using the straight-line approach include unstable x-ray generation caused by deformities in the tape formed by the laser ablation process. Also, the tape drive mechanisms found in conventional equipment capable of providing a substantially constant rate of advancement for the tape are typically very complex means of motion control that are subject to periodic failure, and are often very expensive to both purchase and maintain, not only in terms of direct cost, but also in terms of manpower and equipment downtime. Moreover, the mechanisms and components employed by conventional equipment to precisely position the tape within the targeting area are too often overly sophisticated, which may further lead to periodic failures during tape advancing and thus result in costly up-keep. Accordingly, what is needed in the art are systems and methods for advancing tape is such applications that do not suffer from the deficiencies associated with conventional approaches and equipment.